About: http://webisa.webdatacommons.org/399380769

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	If I can remember correctly, Ramjets need to be at least to the speed of sound to be started, which is why on airplanes such as the SR-71 blackbird, uses a turbojet/ramjet combination in one engine.
http://www.w3.org/ns/prov#wasQuotedFrom	airliners.net